# [plt-scheme] Is there an idiom for throwing away some values?

Here's some code that approximates e^x:
(define (series x)
(call-with-values
(lambda ()
(for/fold ([sum 0]
[factor 1])
([n (in-range 20)])
(values
(+ sum factor)
(* factor (/ x (add1 n))))))
(lambda (sum ignore-me)
sum)))
I'd like to be able to instead do something like
(define (series x)
(just-the-first-value
(for/fold ([sum 0]
[factor 1])
([n (in-range 20)])
(values
(+ sum factor)
(* factor (/ x (add1 n)))))))
... without having to actually write "just-the-first-value" myself :)
Is there an idiom that makes this simpler than what I was doing above?